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SK channels are potassium-selective, voltage-independent, and activated by increases in the levels of intracellular [Ca.sup.2+], such as what occurs during an action potential (1, 2). We have characterized three mammalian [...], In excitable cells, small-conductance [Ca.sup.2+]-activated potassium channels (SK channels) are responsible for the slow after-hyperpolarization that often follows an action potential. Three SK channel subunits have been molecularly characterized. The SK3 gene was targeted by homologous recombination for the insertion of a gene switch that permitted experimental regulation of SK3 expression while retaining normal SK3 promoter function. An absence of SK3 did not present overt phenotypic consequences. However, SK3 overexpression induced abnormal respiratory responses to hypoxia and compromised parturition. Both conditions were corrected by silencing the gene. The results implicate SK3 channels as potential therapeutic targets for disorders such as sleep apnea or sudden infant death syndrome and for regulating uterine contractions during labor.

Presents information on a study on the effect of conditional overexpression of the small conductance calcium-activated potassium channels (SK channels) on respiration and parturition. Characterization of SK channel subunits; Regional distribution of SK protein; Investigation of respiratory patterns under normal and hypoxic conditions; Results and discussion.